FILENAME goptions URL "http://192.38.117.59/~linearpredictors/datafiles/goptions.sas";
%include goptions;

FILENAME url URL "http://192.38.117.59/~linearpredictors/datafiles/readFibrosis.sas";
%include url;

DATA fibrosis; SET fibrosis;
    lyk=log2(ykl40); lp3=log2(p3np); lha=log2(ha);
RUN;    

/* fit polychotomous logistic regression */

PROC LOGISTIC DESCENDING DATA=fibrosis; 
   MODEL stage=lyk lp3 lha/LINK=GLOGIT;
RUN;

/* LR tests are obtained by subtraction */

PROC LOGISTIC DESCENDING DATA=fibrosis; 
   MODEL stage=lyk lp3/LINK=GLOGIT;
RUN; 
  
PROC LOGISTIC DESCENDING DATA=fibrosis; 
   MODEL stage=lyk lha/LINK=GLOGIT;
RUN;

PROC LOGISTIC DESCENDING DATA=fibrosis; 
   MODEL stage=lp3 lha/LINK=GLOGIT;
RUN;

/* fit ordinal logistic regression */

PROC LOGISTIC DESCENDING DATA=fibrosis; 
   MODEL stage=lyk lp3 lha;
RUN;